Crossandra nilotica Oliv.

Flora Zambesiaca Acanthaceae (part 2) by Iain Darbyshire, Kaj Vollesen and Ensermu Kelbessa

Morphology Reproductive morphology Flowers

Flowers in dense terminal pedunculate racemoid cymes to 5 cm long; bracts large, pale green, ovate to elliptic, to 2.5 cm long; bracteoles linear-lanceolate, to 1 cm long.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, sessile, included in corolla tube; anthers monothecous, rounded to finely apiculate.

Distribution

Native of eastern tropical Africa. Occasionally cultivated in the tropics and also grown as a pot plant in Europe and the USA. Zambia, Malawi. Also in Sudan, Eritrea, Ethiopia, Congo, Rwanda, Burundi, Uganda, Kenya, Tanzania and Angola.

Type

Tanzania, Biharamulo Dist., Usui, xi.1861, Grant 135 (K syntype); Uganda, West Nile Dist., Madi, xii.1862, Grant 685 (K lectotype), selected by Vollesen (1990).

Morphology General Habit

Erect or straggling to scrambling shrubby herb to 1.5(2) m tall; young stems finely sericeous- puberulous Shrubby herb to 0.5 m; cystoliths absent.

Morphology Leaves

Leaves in whorls of 4, sparsely puberulous, densest along veins, sessile or petiole up to 1.5 cm long; lamina ovate to elliptic, largest 8.5–12 × 3–3.5 cm; apex subacuminate to acute Leaves dark green, glossy, ovate to elliptic, to 10 × 5 cm; apex acute to acuminate; base decurrent.

Morphology Reproductive morphology Inflorescences

Spike 2–5.5 cm long; peduncle 1.5–6 cm long, puberulous to pubescent

Morphology Reproductive morphology Inflorescences Bracts

Fertile bracts papery, elliptic or broadly so, 16–19 × 11–15 mm, l/w-ratio 1.3–1.6, narrowing gradually to a subacute to rounded tip with a straight mucro up to 1 mm long, sparsely puberulous and with dense capitate glands, pilose on lower part of back and ciliate from long many-celled hairs, with 3–5 longitudinal veins and slightly raised reticulum

Morphology Reproductive morphology Inflorescences Bracteoles

Bracteoles 12–15 mm long, finely puberulous and densely ciliate, with long capitate glands

Morphology Reproductive morphology Flowers Calyx

Sepals acuminate to cuspidate, apical part sparsely puberulous and pilose-ciliate, with capitate glands, dorsal broadly elliptic, 11–14 mm long, ventral ovate-elliptic, 13–16 mm long, lateral 8–10 mm long Calyx divided into 5 unequal sepals, thickened and horny at base, dorsal 2-veined and 2-toothed, ventral and lateral smaller, 1-veined and 1-toothed, to 1 cm long.

Morphology Reproductive morphology Flowers Corolla

Corolla light red to bright red; tube 20–27 mm long, straight, not widened apically; limb 10–15 mm long Corolla bright red, to 5 cm long, split dorsally to give a 5-lobed lower lip and no upper lip.

Morphology Reproductive morphology Fruits

Capsule c.14 mm long

Morphology Reproductive morphology Seeds

Seeds c.3 × 3 mm.

Ecology

Woodland and dry riverine forest; 800–1300 m.

Conservation

Widespread; not threatened.

Acanthaceae (part 2), Kaj Vollesen. Flora of Tropical East Africa. 2008

Type

Types: Uganda, West Nile District: Madi, Grant 685 (K!, lecto.); Tanzania, Biharamulo District: Usui, Grant 135 (K!, syn.)

Morphology General Habit

Erect or straggling to scrambling perennial or shrubby herb to 1.5 m tall; young stems glabrous to sericeous-puberulous

Morphology Leaves

Leaves in whorls of 4; sessile or petiole up to 1.5(–4) cm long; lamina ovate to elliptic, largest 6.5–18(–23) × 2–7 cm, apex subacuminate to acute (rarely rounded), the actual tip rounded, subglabrous to puberulous (rarely pubescent), densest on veins

Morphology Reproductive morphology Inflorescences

Spikes 2–8.5 cm long; peduncles 2–18 cm long, puberulous or sparsely so (rarely pubescent); fertile bracts ovate to elliptic or broadly so (rarely obovate or narrowly ovate), 12–33 × 4–16 mm, length/width-ratio 1.3–2.2(–3), narrowing gradually to an acute tip with a straight mucro up to 0.5 mm long, finely puberulous or sparsely so and with usually dense stalked capitate glands, ciliate on edges (sometimes also on veins) from long manycelled hairs, with 3–5 longitudinal veins and raised reticulum; bracteoles 8–18 mm long, finely puberulous, with long capitate glands, ciliate

Morphology Reproductive morphology Flowers Calyx

Sepals acuminate to cuspidate, finely puberulous and with sparse to dense capitate glands towards tip, dorsal broadly elliptic, 8–17 mm long, ventral ovate-elliptic, 8–17 mm long, lateral 6–14 mm long

Morphology Reproductive morphology Flowers Corolla

Corolla light red to bright red or scarlet (? sometimes orange); tube 20–32 mm long, straight, not infundibuliform apically; limb 10–16 mm long

Morphology Reproductive morphology Fruits

Capsule ± 14 mm long

Morphology Reproductive morphology Seeds

Seed ± 3 × 3 mm.

Ecology

Dry forest, riverine forest, secondary forest, riverine scrub, termite mounds, shaded places in woodland and wooded grassland; 750–1550 m

Note

The description of a 4-lobed calyx with 2 large and 2 small decussate lobes and 2 stamens plus 2 staminodes clearly indicates that Barleria rhynchocarpa is a true Barleria, and that it was erroneously synonymised by Clarke (l.c.). This mistake unfortunately led Cufodontis to publish the combination Crossandra rhynchocarpa. Napper (l.c.) has explained the intricate synonymy of C. nilotica in detail. There are gradual morphological changes from south to north in the distribution area. Southern plants (Tanzania, Angola, Zambia) have wide bracts (length/width-ratio 1.3–2(–2.2)) and long sepals (12–17 mm), while northern plants (Sudan, Ethiopia) have narrow bracts (length/width-ratio 1.7–3) and short sepals (8–13 mm). But the variation is quite gradual with most Ugandan material falling in between, and there is no justification for maintaining subsp. acuminata for the northern form. The lectotype of C. nilotica from N Uganda has sepals 13 mm long and bracts exactly twice as long as wide. The corresponding measurements for the lectotype of subsp. acuminata are exactly the same.

Distribution

Flora districts: T1 T2 T3 T4 K2 T1 T4 Range: Sudan, Eritrea, Ethiopia, Congo-Kinshasa, Rwanda, Burundi, Angola, Zambia, Malawi